Material deposition processes, such as Shaped Metal Deposition (SMD) and Direct Laser Deposition (DLD), are carried out in an inert gas atmosphere to prevent oxidation of the deposited material. Such processes are normally carried out in a chamber, for example with a small internal over pressure, to which the inert gas is supplied.
Conventionally, the inert gas is supplied to the chamber and discarded after use such that a constant supply of the gas is needed. This is inefficient, especially when inert gases having a large specific heat capacity, such as helium, are used as these tend to be expensive.
It would therefore be desirable to reduce the disadvantages of the known process.